Nylen, D., Stout, A. T., & Mitchell, J. R. (1967). Handbook of staff development and human relations training: Materials developed for use in Africa (Revised and expanded edition.). Washington Copenhagen: National Training Laboratories, National Education Association of the United States The European Institute for Trans-National Studies in Group and Organizational Development.

Nylen, Donald, Anthony T. Stout, and J. Robert Mitchell. Handbook of Staff Development and Human Relations Training: Materials Developed for Use in Africa. Revised and expanded edition. Washington Copenhagen: National Training Laboratories, National Education Association of the United States The European Institute for Trans-National Studies in Group and Organizational Development, 1967.

Nylen, Donald, Anthony T. Stout, and J. Robert Mitchell. Handbook of Staff Development and Human Relations Training: Materials Developed for Use in Africa. Revised and expanded edition. Washington Copenhagen: National Training Laboratories, National Education Association of the United States The European Institute for Trans-National Studies in Group and Organizational Development, 1967.